HP R85026A User manual

This manual applies directly to HP R85026A detectors with
serial number 100 and above.
For additional information about serial numbers, refer to
INSTRUMENTS COVERED BY MANUAL in Section I, General
Information.
©Copyright HEWLETT-PACKARD COMPANY 1986
1400 FOUNTAINGROVE PARKWAY, SANTA ROSA, CA 95401 U.S.A.
MANUAL PART NO. 85026-90001
Microfiche Part Number 85026-90002
Printed; FEBRUARY 1986

TABLE ©F eONTENT
Section
Page Section
Page
1 GENERAL INFORMATION
11
OPERATION
Introduction.
, . .1-1
Introduction.
_2-1
Instruments Covered by
Features.
... .2-1
this Manual.
. .1-1
Operator’s Check. ... .2-1
Description.
. .1-1
Operating Precautions.
.. . .2-1
Specifications.
. .1-1
Operating Theory.
. .. .2-2
Safety Considerations.
. .1-2
Detection Modes .
. .. .2-3
Accessories Supplied .
. .1-2
III
PERFORMANCE TESTS
Equipment Required but
. .1-3
Introduction.
.3-1
not Supplied .
Return Loss.
.3-2
Equipment Available.
. .1-3
Flatness.
.3-5
Accessories Available.
Recommended Test Equipment
. .1-4
. .1-4
Dynamic Accuracy .
, .... 3-8
Initial Inspection.
. .1-4
IV
SERVICE
Preparations for Use.
. .1-5
Introduction.
... .4-1
Operating Environment. ..1-6
Cable Troubleshooting.
... .4-1
Storage and Shipment.
. .1-6
Power Cable Replacement .. . . . .4-3
Adjustments .
. .1-7
Ordering Information.
. . . .4-4
Ordering Manual/Microfiche ...
. .1-7
Replaceable Parts.
. . . .4-4
HP R85026A Table of Contents

Section I: General
This manual contains information required to operate, test, and service the Hewlett-Packard R85026A
detector. Figure 1-1 shows the instrument and the accessories supplied with it.
INSTRUMENTS COVERED BY THIS MANUAL
Each HP R85026A detector has a unique serial number. This manual applies to instruments with serial
number 100 and above.
A detector manufactured after the printing of this manual may be different from the detector documented
in this manual. The manual for newer instruments is accompanied by a yellow manual change supplement
that contains serial-specific change information explaining how to adapt the manual for the newer
instrument. In addition to change information, the supplement may contain replacement information that
applies to all instruments, regardless of their serial number.
To keep this manual as current as possible, periodically request the latest manual change supplement.
The supplement for this manual is keyed to its print date and part number, which appear on the title page.
Complimentary copies of the supplement are available from your local Hewlett-Packard office.
UESeRIFTION
The HP R85026A detector is designed to be used with the HP 8757A scalar network analyzer {it is NOT
compatible with the HP 8755C or 8756A scalar network analyzer). The HP R85026A enables the analyzer
to measure either modulated (AC) or unmodulated (DC) test signals.
The HP R85026A detects 26.5 to 40 GHz RF signals at levels from -50 to +10 dBm (AC detection). The
use of three HP R85026A detectors, and two waveguide directional couplers, enables simultaneous
(amplitude only) transmission and reflection measurements via the analyzer CRT.
Table 1-1 lists the HP R85026A specifications.
HP R85026A
General Information 1-1

SAFETY eONSIDERATf
Become familiar with all safety instructions in this manual before you use the HP R85026A detector. This
product was designed and tested in accordance with international standards.
Safety Symbols
WARNING
This indicates a personal hazard. WARNING calls attention to a procedure, practice, etc., that, if not
performed correctly, can cause personal injury. Do not continue past a WARNING until you fully understand
and meet the stated conditions.
This indicates a mechanical hazard. CAUTION calls attention to an operating procedure, practice, etc.,
that, if not correctly performed or adhered to, can cause damage to (or destruction of) part or all of the
instrument. Do not continue past a CAUTION until you fully understand and meet the stated conditions.
CAUTION
The accessories supplied with the HP R85026A detector are shown in Figure 1-1.
Instrument Case
To protect the HP R85026A, when not using the detector, store it in its case.
Hex Balldriver
Use the 3/32 inch hex balldriver to tighten or loosen hex screws when making waveguide connections.
When the HP R85026A is not in use, protect the waveguide with the flange cover.
Cable Markers
When you use more than one detector in a test setup, use the cable markers for identification.
General Information
HP R85026A

EQmPMEHT MdUIRED BUT NOT iUFPLI
To use the HP R85026A detector, you will need a network analyzer and a source.
With the HP 8757A scalar network analyzer, you can make measurements using AC detection (a 27.778 kHz
amplitude modulated signal), or DC detection (an unmodulated signal). The HP 8757A, with up to four
HP R85026A detectors (Opt. 001), measures amplitude levels of -SO to +10 dBm and amplitude ratios
of up to 60 dB (AC detection). For more information, seethe HP 8757A Scalar Network Analyzer Operation
Manual.
To ensure that the HP R85026A meets its dynamic accuracy specification, the HP 8757A must have
firmware revision 2.0.
There are several source options:
® The HP 8350B sweep oscillator with an HP 83550A RF plug-in and an HP 83554A mm-wave source
module.
« The HP 8350B sweep oscillator with an HP 83590 series RF plug-in, an HP 83498 microwave amplifier,
and an HP 83554A mm-wave source module.
® The HP 8350B sweep oscillator with an HP 83572A/B RF plug-in (option 006).
« The HP 8340A or 8341A synthesized sweeper with an HP 8349B microwave amplifier, and an
HP 83554A mm-wave source module.
Note: The HP 8349B microwave amplifier requires a 0.5V/GHz input from the source. See SOURCE
SYSTEM GUIDES in the HP 83554A Millimeter-Wave Source Module R-Band System Manual.
The following equipment is available for use with the HP R85026A detector:
HP R752C/D.Directional Coupler (10 dB/20 dB)
HP R532A.Frequency Meter
HP R382A .Precision Variable Attenuator
General Information
1-3

The following accessories are available for the HP R85026A detector:
HP 11679A.7.6 metre (25 foot) extension cable
HP 11679B .61 metre (200 foot) extension cable
HP 11548A.R-Band waveguide holder (used with waveguide stand)
HP 11540A.Waveguide stand. Locks waveguide holder at any
height from 70 to 133 mm (2.7 to 5.25 in)
HP R362A.Waveguide Low Pass Filter
HP R365A.Isolator. Faraday-rotation-type
HP R910A . F ixed Load
HP R896A.....Standard Section
HP R897A/B...Waveguide 90° Bend (E-Plane/H Plane)
HP R898A/B.Waveguide 90° Twist (R.H./L.H.)
HP R899A/B.Waveguide Straight Section (2.5 cm, 1 in/5.0 cm, 2 in)
HP R914A. S liding Load
HP R920B. Moving Short
HPR921A.Flat Short
The equipment required for testing and/or troubleshooting the HP R85026A is listed in Table 1-2. Other
equipment may be substituted if it meets or exceeds the critical specifications indicated in the table.
INITIAL INSI^ieTION
If the shipping container or cushioning material is damaged, keep it until the contents of the shipment
are checked for completeness, and the instrument is checked both mechanically and electrically.
1. Check the package for completeness. Figure 1-1 shows the items you should receive with each detector.
2. Check connector, cable, and body for mechanical damage.
3. Test the detector electrically. Refer to OPERATOR'S CHECK in Section II.
Notify your nearest Hewlett-Packard office if any of the following conditions exist:
• The instrument does not pass the performance tests and using the procedures in Section IV, Service,
you cannot correct the problem.
• The shipping contents are incomplete.
• There is mechanical damage or defect.
Also, notify the carrier if the shipping container is damaged or if the cushioning material shows signs of
stress. Keep all shipping materials for the carrier’s inspection. Hewlett-Packard will arrange for repairer
replacement without waiting for a claim settlement.
Genera! Information

PREPAHATBONS FOR USE
Rower Requiremenls
Power for each detector is supplied by the HP 8757A scalar network analyzer. Each detector requires
approximately 0.5 watt.
Connect the detector to the analyzer as follows:
1. Insert the HP R85026A multi-pin connector into the analyzer mating connector. The detector connector
is keyed; insert the plug with the key downward.
2. Secure the multi-pin connector in the analyzer by turning the outer shell clockwise.
3. Connect the HP R85026A to the RF output as follows:
CAUTION
Do not apply more than +16 dBm RF power to the HP R85026A.
Using the 3/32 inch hex balldriver supplied, connect the HP R85026A to the RF output with four 4-40 socket
cap screws. The HP part numbers for the two screw sizes most often used are 3030-0209 (0.5 in) and
3030-0349 (0.312 in). Use a 4-40 double chamfer hex nut where required (HP part number 2260-0001).
The HP R85026A input connector is EIA size WR 28 waveguide. This waveguide should mate directly with
a UG-599/U cover flange, and can be mated to a UG-318/U cover flange with the use of an HP 11516A
waveguide adapter.
Use the furnished coded cable clips (cable marker kit) to identify detector cables when you use two or
more detectors. Place matching clips on both ends of the same cable.
General Information
1-5

OPEHATINO ENVIRONMENT
HP R85026A detector operates within the following environmental limits:
Temperature: +20° to +30°C (+36° to +118°F).
Humidity: Up to 95%.
Altitude: Up to 7.620 m (25,000 ft).
Provide maximum protection from temperature extremes. Condensation can occur within the instrument
if it is exposed to temperature extremes or to higher humidity ieveis.
STORAGE AND SHIPMENT
The instrument may be stored or shipped in environments within the following limits:
Temperature; --40° to +75°C (-13° to +167°F).
Humidity: Up to 95%.
Altitude: Up to 7,620 m (25,000 ft).
Provide protection from temperature extremes, which can cause condensation within the instrument.
Containers and materials identical to those used in factory packaging are available through your local
Hewlett-Packard office.
Returning Instrument for Serviee
If you ship the instrument to a Hewlett-Packard office or service center, please include the following
information:
1. Your company name and address.
2. A technical contact person within your company, and their complete phone number.
3. The complete model and serial number of the instrument.
4. The type of service required.
5. Any other information that may expedite service.
When making inquiries, either by correspondence or by telephone, please refer to the instrument by model
number and full serial number.
Genera! Information

ADaUSTMlNTS
There are no operator adjustable components on the HP R85026A detector.
On the title page of this manual is a manual part number and a microfiche part number. Both can be used
to order extra copies of this manual.
Microfiche are 10 x 15 cm (4 x 6 in) microfilm transparencies. Each microfiche contains reduced photo¬
copies of the manual pages.
Also included in the microfiche package are the latest manual changes supplement and pertinent service
notes.
The manual number also appears on the back cover, in the lower left hand corner.
Table 1-1. Specifications (20° to 30°
Frequency Range:
26.5 to 40 GHz
Flatness:
±1.5 dB
Return Loss:
>12dB(^1.67SWR)
Dynamic Accuracy:*
±0.3dB±.03 dB/dB
Referenced to +5 dBm
Typically <±0.5 dB from +10 to -40 dBm
Dynamic Range:
AC +10 to -50 dBm
DC +10 to -45 dBm
Maximum input Power:
+16 dBm
Dimensions:
Cable length is 1.22 m (48 in)
Weight:
Net 0.24 kg (0.5 ib);
Shipping 1.0 kg (2.2 Ib)
Input Connector:
EIA size WR 28 waveguide
Cover Flange: UG-599/U
' With HP 8757A firmware revision 2.0 or higher.
General Information 1-7

Table 1-2. Recommended Test Equipment
Instrument
Critical Specifications
Recommended Model
Use*
Network Analyzer
R85026A AC/DC compatible
HP 8757A with firmware
rev. 2.0 or higher
0,P
mm-Wave Source System:
26.5 to 40 GHz
0,P
Sweep Oscillator
RF Plug-In
8757A compatible
HP 8350B
HP 83550A**
Source Module
WR 28
HP 83554A
Directional Coupler
26.5 to 40 GHz
WR 28
HP R752C
P
Detector
26.5 to 40 GHz
HP R85026A
P
Short
26.5 to 40 GHz
WR 28
HP R921A
P
Low Pass Filter
26.5 to 40 GHz
WR 28
HP R362A
P
Isolator
26.5 to 40 GHz
HP R2365A
0,P
Power Meter
With frequency
compatible sensor
HP 436A
p
Power Sensor
26.5 to 40 GHz
HP R8486A
p
Variable Attenuator
0 to 50 dB; 0.5% accuracy
HP R382A Opt. 890
p
Digital Voltmeter
Accuracy: ±0.01%
Input !mpedance>10M ohms
HP 3456A
s
Phillips Screwdriver
Size 0 Point
HP P/N 8710-0978
s
Fiat Blade Screwdriver
HP P/N 8730-0008
s
Hex Nut Wrench
1/2 X 7/16
HP P/N 8720-0009
s
’ 0=Operator's Check P=Performance Tests S=Service
” The HP 83550A can be replaced by an HP 83590 Series plug-in and an HP 8349B microwave amplifier.
General Information

Section II: Operation
INTRODUCTION
This section contains information concerning the operation of the HP R85026A detector.
WARNING
Never look directly into the open end of a piece of waveguide when it is
connected to a source of microwave energy. Microwave energy Is
extremely harmful to the eye.
The HP R85026A features are shown in Figure 2-1.
OPEUATOWS CHECK
The OPERATOR’S CHECK {at the end of this section) verifies that the HP R85026A is functioning correctly.
It does not thoroughly check all specifications to their limits, but it is an appropriate test for daiiy instrument
verification, incoming inspection, or verification after digital circuit repair or replacement.
©PERATINC PRECAUTIONS
CAUTION
Do not apply more than +16 dBm RF CW power to the HP R85026A, or
damage can occur.
Do not drop the HP R85026A or subject it to mechanical shock. The
detector is easily damaged.
2-1

2. MULTI-PIN CONNECTOR supplies the necessary DC voltage (from the analyzer) for the operation of the
HP R85026A, and feeds the detector output signal to the network analyzer.
1. RF INPUT CONNECTOR {WR 28 waveguide) accepts the RF signal.
Figure 2-1. HP R85026A Features
OPERATING THEORY
The HP R85026A detects and adapts an input signal in the frequency range of 26.5 to 40 GHz that is either
an unmodulated RF signal (DC detection mode) or a squarewave amplitude modulated RF signal (AC
detection mode) so that it can be displayed on the HP 8757A scalar network analyzer. In either AC or DC
detection mode, the detector provides a 27.778 kHz squarewave signal for the analyzer to interpret and
display.
In AC detection, an RF or microwave signal is amplitude modulated with a 27.778 kHz squarewave. The
HP R85026A demodulates (envelope detects) the signal to produce a 27.778 kHz squarewave whose peak-
to-peak voltage corresponds to the RF signal magnitude at the detector input. This signal is amplified
and passed to the analyzer.
In the DC detection mode, no modulation is required. The HP R85026A detector converts the RF signal
to a proportional DC voltage that is then chopped at a 27.778 kHz rate. This chopped signal is amplified,
and passed to the network analyzer.

MEASURIMENT SYSTEM e©NFi@yRATi©N
DETEOTION
You do not have to set AC detection on the analyzer unless DC mode was used In the previous
measurement (even If the HP 8757A is turned off, it remembers the measurement mode). If the last
measurement was in DC mode, press [SYSTEM] and select [MODE AC/DCj to turn AC mode on (AC lights
up). You can also press [PRESET] to set the AC detection mode; AC detection is automatically set when
the analyzer presets.
For the majority of measurements, AC detection is the preferred method. It offers greater sensitivity and
immunity to noise and drift with time and temperature. AC detection amplitude measurements require
a modulated test signal. Modulation is provided via an internally modulated source (e.g. the HP 8350B),
or from the HP 8757A rear panel modulator drive. Test set connections depend on the source; Figure 2-2
illustrates a typical measurement.

BC D@teetl0n Mod©
DC detection offers greater power measurement accuracy and the ability to characterize oscillators and
modulation sensitive devices. To use DC detection, you must first set the DC measurement mode on the
HP 8757A. There is also a zeroing operation used in the DC mode that compensates for the effects of
DC drift and temperature fluctuations.
The ability to make DC measurements and the softkeys specific to DC mode are not automatically
accessible. The HP 8757A must acknowledge the presence of an AC/DC detector either at preset, or via
the [CONFIG SYSTEM] softkey in the CAL menu.
1. Connect the equipment as shown in Figure 2-2.
On the HP 8757A:
2. Press [PRESET].
During preset:
« The analyzer reads each input port and identifies the detector or bridge connected to it (AC/DC
or AC only).
® The HP 8757A enables the DC mode softkeys (when an AC/DC detector or bridge is identified).
Now you can access [DC DET ZERO] (in the CAL menu) and [MODE AC/DC] (in the SYSTEM
menu).
3. To turn on the DC mode, press [SYSTEM] and select the softkey [MODE AC/DC]. AC dims and DC
lights up.
When you select DC mode with the softkey [MODE AC/DC], the analyzer turns OFF the source internal
squarewave modulation (HP 8350B) and disables the analyzer’s rear panel modulation drive output
(used with the HP 8340A/41A).
You can also have the analyzer read the inputs without using [PRESET]: Press [CAL] and select the
softkey [CONFIG SYSTEM].
If you remove and/or exchange a detector, you must reconfigure the system, using either [PRESET] or
the softkey [CONFIG SYSTEM], so that the correction factors match the port and device.
DC lereing. When you make a DC mode measurement, you should perform a zeroing operation
to compensate for the effects of DC drift and temperature fluctuations (this is not required for AC
detection). The zeroing operation eliminates small DC voltages from the diode detector that would
otherwise cause amplitude measurement errors at low (-40 dBm and below) power levels.
On the HP 8757A:
1. Press [CAL] and select [MORE] [DC DET ZERO]. The analyzer displays SELECT DC DET ZERO.
2. Select [AUTOZROJ. The analyzer displays AUTOZERO IN PROGRESS ... and then AUTOZERO
COMPLETED.
Operation

Repeat Autozero, [REPT AZ ON/OFF], repeats autozero at a selected interval ([REPT AZ TIMER]).
Repeat Autozero Timer, [REPT AZ TIMER], allows you to set the time interval for the Repeat Autozero
(from 1 to 60 minutes).
Manual Zero, [MANUAL], is similar to zeroing a power meter. First, remove the RF signal from the detector.
Then select [MANUAL] to perform the zeroing.
NOTES; If a device under test generates RF signals or noise, Autozero is not valid. Devices that can
generate RF energy are microwave amplifiers and mixers with the local oscillator signal applied. If you
are testing such devices, use Manual Zero.
For optimum performance, the source RF output waveguide must be electrically connected to the detector
input waveguide when zeroing.
It is good practice to perform a DC zero operation every five minutes, and before making a low level
measurement. This is especially important if the operating environment temperature changes significantly
(several degrees centigrade).
Refer to the HP 8757A Operating Manual for detailed softkey information.
HP R85026A
2-5

©PiUATOH’S OHEOiC
DESCRIPTION
The operator's check verifies that the HP R85026A is functioning properly, it does not thoroughly check
all specifications to their limits, but is an appropriate test for daiiy instrument verification, incoming
inspection, or verification after repair or replacement of digital circuits. It consists of checking the detector
over a 50 dB range.
POS Z BLANKING
Figure 2-3. Equipment Setup for Operator’s Check
EQmPMEm
Sweep Oscillator Mainframe .HP 8350B
RF Plug-in.HP 83550A
mm-Wave Source Module.HP 83554A
Variable Attenuator.HP R382A
Isolator . . . H P R365A
Scalar Network Analyzer.HP 8757A
Operation

PBOCEBURE
1. Connect the equipment as shown in Figure 2-3. Allow 30 minutes for warm-up.
On the HP 8757A:
2. Press [PRESET] to preset both the analyzer and the source.
On theHP8350B:
3. Press [START] [2] [6| [.] [5] [GHz].
4. Press [STOP] [4] [0] [GHz].
On the HP 8757A:
5. Select the softkey [CHAN 2 OFF] to turn off the channel 2 trace.
NOTE: The first time through the procedure, you are checking the detector in the AC detection mode
{AC is analyzer default condition).
6. Press [CAL] and select [MORE] [DET OFFST]. The analyzer displays SELECT DETECTOR OFFSET.
7. Select [DET A], The analyzer displays A DETECTOR OFFST and the value of the offset.
8. Press [0] [ENT] to ensure that the detector offset is zero.
NOTE: When using DC mode, perform DC zeroing:
a. Select [PRIOR MENU].
b. Select [DC DET ZERO].
c. Select [AUTOZERO].
On the HP R382A attenuator:
9. Set the attenuation to 0 dB.
On the HP 8757A:
10. Press [CURSOR]. A cursor (-h) appears at the center of the trace. Note the CRSR value displayed
in the CRT’s active entry area.
On the source;
11. Adjust the output power level until the cursor value on the CRT reads +5 dBm.
On the HP R382A attenuator:
12. Set the attenuator to 50 dB of attenuation.
On the HP 8757A:
13. Press [AVG] and select [AVG ON/OFF] to turn averaging on (ON lights up). The default average factor
of 8 is displayed on the CRT. Wait approximately seven seconds for the trace to settle.
14. Press [CURSOR]. The active entry area should display a cursor value of -45 dBm ±3 dB.
15. Press [AVG] and [AVG ON/OFF] to turn averaging off.
16. Press [SYSTEM] and select [MODE AC/DC] to turn DC on.
17. Repeat steps 6 through 14 to check the detector in the DC detection mode.
If the HP R85026A does not pass the OPERATOR’S CHECK, refer to TROUBLESHOOTING in
Section IV, Service.
2-7/28